Automobile Maintaining Your Air Filter

In most modern vehicles, the air filter is under the hood inside a rectangular cold air collector box that’s located up near the front of the engine compartment. (Other vehicles, including those with carburetors, have big round metal air cleaners that are hard to miss) the air cleaner has a large air inlet duct (also called the air intake hose) connected to it. Loosen the hose clamp that seals it to the box, and then undo all the screws, clamps, or wing nuts that hold the lid of the box in place.

Put the fasteners you removed somewhere safe so that they don’t roll off into oblivion. Open the lid of the box and . . . voila!. . you should find the air filter inside.

Some older vehicles have permanent air filters, and some off-road vehicles have more-complex filters with wet and dry elements. Clean and replace these according to the instructions in your owner’s manual. If you don’t find a pleated paper, cotton, or gauze filter inside your air cleaner, you probably have one of these alternatives.

Checking and cleaning your air filter and cold air collector box

whether your air filter needs to be replaced, just hold it up to the sun or to strong light. Can you see the light streaming through it If not, try dropping it lightly, bottom side down, on a hard surface. Doing so should jar some dirt loose.

If the filter is still too dirty to see through after you’ve dropped it a few times and it looks as though it just needs a bit of cleaning, you can try to clean it following the directions below. If that doesn’t work, you need a new one.

To clean a pleated air filter either use an air hose to blow the dirt off (not through) it or a vacuum to suck it out. For both methods, handle the filter gently to avoid crushing the pleats. Keep the nozzle of the air hose or vacuum cleaner several inches away from the filter — don’t jam it up against it. And if you’re using compressed air, do it away from the vehicle to avoid blowing the dirt around under the hood.

To clean a pleated air filter either use an air hose to blow the dirt off (not through) it or a vacuum to suck it out. For both methods, handle the filter gently to avoid crushing the pleats. Keep the nozzle of the air hose or vacuum cleaner several inches away from the filter — don’t jam it up against it. And if you’re using compressed air, do it away from the vehicle to avoid blowing the dirt around under the hood.

I prefer a “hand vac” for this job. You don’t have to buy a compressed air gun or schlep the car to a service station to use theirs (and some of them are now charging for the air!). Also, with a hand vac, you run less risk of blowing the dirty air out of the cold air collector box and into something else. I keep a battery-powered hand vac in the trunk of my car to do stuff like this as well as to get the dirt off the floor mats and to clean the upholstery.

Buying and replacing an air filter

Because the air filter extracts dirt and dust particles from the air, you should change it at least once a year or every 20,000 miles, whichever comes first — unless yours gets very dirty before then.

Last word

If you do most of your driving in a dusty or sandy area, you may need to replace your air filter every 5,000 miles or less. If a road trip takes you to such an area, it’s a good idea to check the air filter right after you return.